Quoting directly from toPuertoRico.org, One unique characteristic of a Puerto Rican wedding is the bridal doll. A bridal doll, in a dress identical to the brides' gown, is usually placed on the head or center table with souvenirs attached to its dress. During the reception, the bride and groom will walk to each person and thank him or her for their presence at the nuptials. Each person is then pinned with a souvenir, some people in return pins dollars into the doll's dress.
For the non-vegitarian Wedding parties, consider a Puerto Rican tradition (not necessarily wedding tradition), "Lechon" or Pig Roast. For the vegitarian crowd or as an addition to your Lechon try some fried plantains "tostones"